Vacuum-tube circuits



Jan. I, ``1 92 8..

R. L. DAVIS .VAGUUM TUBE CIRGUITS- Flled Jan 22 1924 .w R ma. w ma w ATTORNEY foto fttlt Wl1a S T .A T E S JL. DAVIE,

lafiflfi PATENT OFFICE.

nnncrnrc o nnnnnnernnrne oonrnnr, A eonronn'rron or rnn'ne'rnvnrirn.

`.tliplcaton filed January 22., 1924-.

: quency generator including` epparatns tor ineertion in the grid leads oil? the generator triodes whichv will stahilize the operation o'li the generator triodes, increase the etlicien-;zy ot operation? aild dainp out paraeitic oscillations. i

lin the construction ot radio-ttrequeinry `zgonerators containing` thern'iionic triodes, ditticnlty is trequently experienced in adjust ion; the feed-hack nienns connected to the irid circuite.. lit has heen found that an nndceirahly large ainonnt ot indnctance n'iay he required in the grid circuit, rcsulting in the production oit a high voltage upon the grid which makes the operation tronhlc- :tonie and nnntnblc. 'lfhie e'ltect ie particularly unclesirable upon apparatns 'tor the generation o'l extreincly ehort Waves.

l have found that the ineertion ot a treqnency trap in the gricl circnits inarlzedly increases the stahility ot operation ot a triode oecillator. lt have tin'ther found that it avoide paraeitic oscillatione and that it ei'ifihlee the oinployinent ot a much lower wrid voltageu lither objects and etrrictural details ot nry inrention 'will he al'iparent :troin the follow inn; description 'When read in connection 'Wi th the accompanyingg drawinfge, Whercin:

'lhe single ligure is e (liftgi'enin'iatic view ot epparatue and circ-uits einhodying niy invention.

lin the igln'e are shown four triodee 1, 2, 3 and 4, 1 and 2 being oecillator triodes and 3 and ll being lnodnlator triodes, connected according to the l-lteising Constant-current inodnlation system. r.the fignre ale shows an aerial o, a connterpoise (i and an nductance i" connected therehetween.

The cuetoinary conections ;tor the Heising constant-cin'rent inodulation s etein are asseinhled ahont the triodee and aerial system. rthe sjjfetein ot conncctione also contains filter trans ll and 12 connected to the grid electrodee ot triodes l and 2, reepectively. Energy 'tor actnation ot the system is tnrnished Serial No. GB'F,'?M.

by a high voltage direct-current source lat :tor the plate circuits, and a low voltage source 15 tor the iilainents.

ln the operation ot my device9 the triodes are energized troni the current .sources in the neual inanner, and oscillations are generated in triodes 1 and 2 and in. the connected iiulnctaimee. 'these oecillntions are stahilized by the presence ot .filter trapo 11 and 12 which npparently ,serve to adjnst the phone li placeinent i'ieceefserv hcti'veen the plate current and grid potentiah bringing this relotion more precisely to the proper value,

thorehy producing a reduction in the magnitnde ot the oscillating voltage required at the gricl electrodes.

:tind that the resonant oscillation trequeney ot lilter traps ll and 12 ie :not at all critical. rll`hc resonance treqnei'icy ot these trans inay dittfer by a enbstanti'fil percentage troin the osoillation frequency, generated hy the System as a whole, without diininntirm ot their etfectivenese. its he'fore euggested, the action ot these lilter trape appeare to he that of adjnsting and correcting the phase 1*:

relation between the plate current Variation and grid potential Variation. 'lhis action has not as yet' been conclrlsively proven and the advantage gained thereby inny he due to other phenomena.

VVhile I have shown onlyT one enihodiinent ot niy invention in the accoinpanving drawings, it is capable ot various changes and niodifications Without departinn; tron] the spirit thereot', and it ie (leeirecl', there'lorc, that only Such lin'iiint-ions shall ho ;in'ipoeed thereon ue are ;found in the 'ion' art oi' :ircV indicated in th*j :ipijiendml claim.

clahn as niy invention:

l'n a 'vacrnin'i-tnhe device a plurality ot vacuuin tuhes each provided. with a `grid, a network including said t-uhes and a conductor connnon to all Oit said grids, said condnctor havingl hranchee, one branch entered inp; to each grid, end parallel-resonant circuits, one in each ot' said hranchce, the resonance frequency ot said parallel-resonant circuits being appi'oniniately that at which perasitic currents tend to occnr in said net- Work.

ln teetiniony Whereo't, I have herennto suhscrihed my nfune this 15th day of Join uary, 1921i.

ROBERT L. DAVIS.

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